1. Field of the Invention
The present invention relates to photovoltaic (PV) modules and film laminates, and more particularly to PV modules and film laminates having improved heat transfer characteristics and employing a mechanism for utilizing heat absorbed by the module via solar radiation.
2. Description of the Prior Art
Simultaneous collection of electricity and heat from a solar panel has been attempted in a variety of configurations.
Individual solar photovoltaic modules of varying type have been attached to transpired, hot air solar collectors such as that described in U.S. Pat. Nos. 4,934,338 and 6,870,087. Also, heat has been collected from behind photovoltaic curtainwall assemblies, such as the library at Mataro, Spain.
Although it is known in the industry that high module temperatures can inhibit electrical output and that the majority (80-95%) of absorbed solar energy to the module is re-emitted as heat, few attempts have been made to improve the thermal performance of solar photovoltaic modules themselves for collection of waste heat.
Many methods have been created to alter photovoltaic modules to exhibit other desired properties, such as transparency or different colors. Several methods exist for allowing thin-film photovoltaic modules to exhibit a certain degree of transparency. These methods involve etching, scribing or scoring layers away to reveal “windows” in the module.
Solar cells exist with “through-holes” for the purpose of providing a conductive pathway from the front electrode to the backside electrode, such as U.S. Pat. No. 3,903,427 and U.S. patent application Ser. No. 11/278,645. Interconnection of cell electrodes established via conductive through-holes eliminates the need for extensive conductive grid busses, reduces shading effect therefrom, reduces deleted area for scribe lines and allows for larger individual cells. Such solar cell through-holes are not formed entirely through the solar module from front to back. Indeed, owing to moisture concerns (specifically, keeping moisture out of the inner portions of a PV module), one would never form a hole entirely through a PV module in a conventional module.
Further, while several module framing and mounting methods are designed to improve heat transfer from a typical photovoltaic panel, few if any panel constructions are designed with the express purpose (among others) of increasing and improving heat transfer to the rear of the photovoltaic module.
For the purposes of the present disclosure, a method of forming a typical thin-film photovoltaic solar module such as that disclosed in U.S. Pat. No. 4,315,096 (and improved over the years) can be simplified as:                1) Deposition of conducting layer upon electrically-insulating substrate;        2) Longitudinal scribing of conducting layer (via chemical or mechanical etch, or laser) to establish isolation of individual cell units in a “first scribe”;        3) Deposition of semi-conducting thin film active layers (e.g. p-i-n single junction);        4) Longitudinal scribing of semi-conducting thin film layers), while keeping underlaying conductive layer intact, in a “second scribe”;        5) Deposition of transparent conductive oxide (TCO) front contact layer;        6) Longitudinal scribing of front contact layer and semiconducting thin film active layer, while keeping underlaying conductive layer intact, to establish serial connection between individual cells in a “third scribe”;        7) Optional placement of conductive grid of busses atop TCO layer to assist in carrying current;        8) Placement of encapsulant sealing material (e.g. ethylene vinyl acetate (EVA), Polyvinylbutyral (PVB) thermoplastic resin or 2-part epoxy).        9) Placement of transparent frontsheet (e.g. glass or plastic) and module encapsulation (using e.g. vacuum press).        
Typical intermediate or following steps include placing of wiring terminals, testing of module electrical output and final panel packaging and framing.
For superstrate deposition the process is similar, where the largest difference is that thin film deposition occurs on the front coversheet and contact materials, and final encapsulation includes the rear protective layers (e.g. encapsulant materials and glass or plastic rearsheet).
Proper encapsulation of the module is necessary to ensure protection of the solar cells from exposure to the elements. Protection from moisture ingress, physical impact, and dirt are primary concerns to the long-term functioning of the PV cell.